Let-7d-5p improves mouse cognitive function by targeting bach1 in Alzheimer's disease

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• MicroRNAs (miRNAs) are critical regulators in Alzheimer's disease (AD) pathogenesis.
• The lethal-7 (let-7) family, including let-7d-5p, plays a role in cell apoptosis, differentiation, and immune response.
• Understanding let-7d-5p's function in AD is crucial for developing novel therapeutic strategies.

Purpose of the Study:

• To investigate the role and mechanisms of let-7d-5p in Alzheimer's disease progression.
• To determine if let-7d-5p can ameliorate Aβ-induced neurotoxicity and cognitive deficits.
• To elucidate the molecular targets and pathways regulated by let-7d-5p in AD.

Main Methods:

• Utilized APP/PS1 transgenic mice and SH-SY5Y neuroblastoma cells.
• Administered let-7d-5p overexpression via adenovirus vectors in vivo and in vitro.
• Assessed cognitive function using the Morris water maze test and evaluated neuropathology via H&E and Aβ immunohistochemistry.
• Measured cell viability, apoptosis, and protein expression (bach1, Bcl-2, cleaved caspase-3) using MTT assays, flow cytometry, RT-qPCR, and Western blotting.
• Verified let-7d-5p and bach1 interaction using luciferase reporter assays.

Main Results:

• Overexpression of let-7d-5p enhanced cell viability, inhibited apoptosis, and reduced oxidative stress in Aβ_1-42-treated cells.
• let-7d-5p overexpression improved cognitive function, attenuated hippocampal pathology, and decreased Aβ deposition in AD mice.
• let-7d-5p directly targets bach1, repressing its expression and counteracting Aβ-induced cellular injury and cognitive deficits.
• Bach1 upregulation reversed the protective effects of let-7d-5p, confirming bach1 as a key mediator.

Conclusions:

• Let-7d-5p exerts neuroprotective effects in Alzheimer's disease.
• let-7d-5p alleviates cognitive deficits and neuropathology by inhibiting Aβ deposition and neuronal apoptosis.
• The therapeutic potential of let-7d-5p in AD is mediated through its targeting of the bach1 pathway.